Room temperature sol-gel synthesis of crystalline Cs[V3O8]. Probing the hydration level of the interlamellar space by V-51 and Cs-133 MAS NMR spectroscopy

The caesium vanadium oxide phases Cs[ V3O8] and Cs2[ V6O16]$ 0.7 H2O were synthesized by a room temperature process, a promising alternative method to traditional routes to MV3O8 phases. The characterization of these compounds and Cs4[ H2V10O28]$ 4H2O by powder X- ray diffraction, SEM and solid- state NMR is provided. In particular, we used 51 V and 133 Cs MAS NMR to investigate the local environment of caesium and vanadium nuclei and 2D 1 H / 133 Cs CP MAS HETCOR experiments to explore the spatial connectivities between caesium ions and water molecules in the interlamellar space. The results obtained on Cs2[ V6O16]$ 0.7 H2O illustrate how powerful solid- state NMR can be to study structurally disordered materials.